Piezoelectrically ignited gas torch



April 1, 1969 "r. F. DEUCHER PIEZOELECTRICALLY IGNITED GAS TORCH FiledMarch 15, 1967 28 INVENTOR.

THEODORE F.DEUCHER MW ATTORNEY United States Patent 3,436,164PIEZOELECTRICALLY IGNITED GAS TORCH Theodore F. Deucher, Par-ma, Ohio,assignor to Clevite Corporation, a corporation of Ohio Filed Mar. 15,1967, Ser. No. 623,293 Int. Cl. F23q 7/12 US. Cl. 431-255 21 ClaimsABSTRACT OF THE DISCLOSURE This invention relates generally to a gastorch and, more particularly, to a torch of the type having apiezoelectric spark generator for igniting the gas at the nozzle outlet.

In the prior art piezoelectrically ignited gas torches of various typesare already known, for instance, see copending application Ser. No.183,830, filed Mar. 30, 1962, assigned to the same assignee as theinstant invention and Patent No. 3,255,803. Similarly known are gastorches equipped with battery powered spark igniters, see Patent3,155,140.

One of the problems with self-igniting torches generally stems from thedifficulty of devising an electrically operable structure, particularlya nozzle portion, which will not interfere with or otherwise affect thegas flow. The insulator must be protected from the heat of the flame,and because of the small amount of energy available, usually only enoughfor one tiny spark, electrical losses due to leakage must be kept to anabsolute minimum.

Applicant has recognized that these and other related shortcomings maybe overcome by providing a bare, needle type, electrode supportedconcentrically within the nozzle by an insulator located remote from thetip with cooling being provided by physical contact of the electrodewith the combustible gas. Furthermore, the torch, and more particularlythe ignition system thereof, is constructed and arranged in such mannerthat the voltage increase phase, i.e. the period until a sufiicientlyhigh voltage level for sparking is achieved, takes place in a segment ofthe torch unaflected by electrical leakage at the tip. This is achievedby providing a voltage breakdown control gap in the ignition circuitwhich prevents ionization in the gap until the proper voltage level isreached, i.e. by providing a resistance across the voltagecontrol gapwhich is substantially greater than the effective resistance across thespark gap. Consequently, dissipation of electrical energy proximate tothe bare electrode and a potential misfiring as a result of such leakageis thereby eliminated. In addition, the ignition device provides enoughenergy for several sequential sparks at each operation.

It is therefore the primary object of this invention to provide apiezoelectrically ignited gas torch which obviates the difficultiesexperienced by prior art devices.

It is another object of this invention to provide a piezoelectricallyignited gas torch in which a needle electrode is utilized which offersprotection against premature ignition, and which is effective to providea plurality of sequential sparks with a single actuation of the igniterto assure ignition.

Another object of this invention is to provide a torch of the type abovedescribed in which a voltage control Patented Apr. 1, 1969 spark gap isutilized to block the voltage flow until a sufficiently high level isreached to ionize and break down to gap so as to cause the electricalenergy to spark strongly across the igniting spark gap located in thenozzle.

It is another object of this invention to provide a gas torch of thetype hereinabove described in which the nozzle and gas conduit portionas Well as the electrode housed therein or aflixed thereto are quicklydisconnectable from the handle or main body of the torch.

It is another object of this invention to provide a gas torch of thetype as above described in which the lever for manually actuating thepiezoelectric igniter is also effective to operate the main gas supplyvalve.

For a better understanding of the present invention, together with otherand further objects thereof, reference is had to the followingdescription taken in connection with the accompanying drawings, and itsscope will be pointed out in the appended claims.

An aspect of the present invention resides in the provision of apiezoelectrically ignited gas torch which includes a handle which formsa housing and a valve arrangement secured to the handle and connectibleto a source of gas under pressure. A nozzle with a customary outlet isprovided and a conduit extends from the nozzle and is mounted within thehandle. The nozzle and the conduit are formed at least in part ofelectrically conductive material. A small tube extends between theconduit and the valve for providing a fluid passageway there between.Disposed Within the handle is a piezoelectric igniter which iseffective, upon actuation thereof, to provide a high voltage sparksource. An electrical circuit is operatively connected to the igniterand extends between the latter and the nozzle. A solid, axiallystraight, cylindrical metal electrode, such as a needle type electrode,is electrically coupled to the circuit and is substantiallyconcentrically arranged within the nozzle. In the preferred embodiment,the tip of the electrode forms a point and terminates proximate to thenozzle outlet to form a spark gap.

An aspect of the present invention resides in the provision of apiezoelectric ignition device which includes a manually actuatedpiezoelectric voltage generating system effective, upon actuationthereof, to provide a high voltage spark source. An electric circuit isassociated with the piezoelectric generating system for transmitting thegenerated voltage. The circuit includes a spark air gap and a voltagecontrol gap arranged in series with the control gap and elfective toblock the voltage across the gap until the voltage within the circuithas reached a predetermined level, whereby the voltage then ionizes thecontrol gap and without any substantial dissipation of energy sparksacross the spark air gap.

In the drawing:

FIGURE 1 is a perspective view of the gas torch hereinunderconsideration;

FIGURE 2 is a side view portion of the torch shown tion; and

FIGURE 3 is a side view of the handle with one half thereof removed toshow the individual components (some of them in cross section) securedtherein.

Referring now to the drawing there is shown in FIG- URES 1 to 3 a torch10 which includes a hollow handle 12 molded of plastic material, in twohalves, one of which is shown in FIGURE 3. The two halves are heldtogether by transversely protruding bolts (not shown) and a metal sleeve11 with a radially inwardly turned flange (not visible) slipped over thetwo handle halves. The internal configuration of the handle 12 is suchthat it may suitably receive at one end thereof a valving arrangement 14having at the rear end a threaded gas inlet 16 connectible to a sourceof gas under pressure and a of the nozzle and conduit partly inlongitudinal secgas outlet 18 connected to the inlet by passageways 20,21 which are effective to permit the gas to flow therebetween. A tubularextension 24, extending integrally and perpendicular to the longitudinalaxis of the valve body 14 and intermediate the ends 16 and 18, isprovided with a fluid passageway 22 which terminates into a junction ofpassageways 20, 21 above mentioned. The tubular extension 24 receiveswithin an enlarged segment of the passageway 22 a flame control valve 26which includes a stationary hollow cylindrical member 30 threadedlysecured within the passageway and adapted to receive a piston 32 havingat one end a circular handle 28 for manual manipulation of the valve.The piston is sealingly disposed within member 30, see O-ring 33, andextends transversely into the passageways 20, 21 to control the flow ofgas between the inlet and outlet 16 and 18, respectively, by effectivelyblocking the junction of the passageways.

The forward passageway 21 is adapted to receive therein a plungerresponsive shut-off valve 34 of the type used in automotive tires. Thevalve 34 completely blocks the fluid flow through the passageway 21 andthe fluid is forced to flow through the channels of the valve 34 inresponse to actuation thereof by means of a push rod 84 which causes aplunger 35 of the valve 34 to be moved axially inward to open the valvewhile the plunger is maintained in that position. The gas which ispermitted to flow through valve 34 empties into fluid chamber 36 andfiows thereafter through tubing 38 toward the forward section of thetorch.

The tube 38 terminates into a bayonet type quick disconnect and couplerassembly having a spring biased female member 40, see FIGURE 3, and acomplementary male member 42, the latter forming a part of gas conduit46 as shown in FIGURE 2, which is inserted into the female member for afluid tight connection. The members 40 and 42 are securely held togetherby a pin 43 and groove 45 arrangement, the pin 43 extending radiallyfrom the interior surface of the female member. The groove 45 issubstantially L-shaped and formed in an enlarged diameter segment 47 ofthe male member. The male member is provided with a radial opening 44 topermit air to enter into the conduit 46 for mixing, in suitableproportion, with the gas such as acetylene. The gas carrying conduit 46is integrally connected with the male member 42 of the quick disconnectdevice and terminates at the opposite end into a nozzle portion 48. Thenozzle 48 is or a tubelike construction and the axes of elongation ofthe nozle and the conduit 46 intersect and define an included angle ofnot less than 90. The nozzle 48 has a tubular extension 50 locatedremote from the nozzle outlet 54 and this tubular portion 50 is axiallyspaced from the intersection of the axis. The gas thus flows through theconduit 46 and into the nozzle 48 and exists through the tapered portion52 and ultimately through the nozzle outlet 54. In order to accommodatethe electrical system, which is hereafter described, the nozzle 48 andthe conduit 46 including the quick disconnect and coupler members 40,42, are formed of, at least in part, electrically conductive material.

Turning now to the electrical characteristics of this invention, thereis shown in FIGURE 3 a piezoelectric generator assembly 56 of the typeshown and described in copending application Ser. No. 574,103, assignedto the same assignee as the present invention. The assembly 56 comprisesa plurality of piezoelectric elements 58 having a center electrode 66and being disposed within a rigid frame 60. The frame is movablyanchored within the interior of the handle 12. A rolling cam arrangement(not shown) in conjunction with a manually actuated lever 62 is adaptedto squeeze the piezoelectric element 58 along its longitudinal axis andagainst the frame 60 so as to generate an electric potential. Details ofa piezoelectric igniter generally are well known in the art and furtherreference may be had to US. Patents 4 3,093,333, 3,101,420 and3,114,059. The push rod 84 is pivotally mounted to the lever 62 and iscaused to move axially rearward in response to actuation of the lever.Electrically connecting to and extending from center electrode 66 is alead wire 64 which terminates at the opposite end by means of a metalpin 68 slightly beyond the exterior surface of the handle 12 and morespecifically at the end face 13 thereof. The lead wire 64 is suitablyinsulated and the uninsulated portion 68 of the lead wire 64 is encasedin a ceramic insulator sleeve 70 rigidly mounted in the handle 12.

Referring now again to FIGURE 3, the electric circuit includes, asidefrom the components already mentioned, a lead wire 72 and a terminalassembly composed of a housing 74 for securely receiving a ceramicinsulator sleeve 76 which houses the terminal portion of lead wire 72and, in the same manner as aforedescribed With respect to the terminalend of lead wire 64, there is arranged a metal pin type electrode 78which extends from the lead wire 72 to the exterior surface of theceramic sleeve 76 and, in assembled condition of the torch, the frontfaces of the electrodes 68 and 78 are mechanically as well aselectrically juxtaposed and the space therebetween thus does not vary toprovide a voltage breakdown control gap which is effective to preventionization between the gap end until the proper voltage level is reachedin the system and more specifically in that portion of the systemconstituted by members 66, 64 and 68. The lead wire or electricalconductor 72 is insulated from and extends externally alongside theconduit portion 46 in suitable metal tubing 73 and terminates into thetubular extension 50 of the nozzle 48.

Within the tubular extension 50 there is disposed a ceramic sleeve 80for rigidly securing and insulating from the metal nozzle a solidaxially straight, cylindrical metal electrode 82, preferably a bareneedle type electrode, which extends concentrically through the nozzleand terminates substantially flush with the nozzle outlet 54. The spacebetween sleeve 80 and end cap 81 of tubular extension 50 is filled withsuitable insulating material. The needle electrode is tapered toward theoutlet 54 and the terminal end constitutes a point electrode which formstogether with the outlet 54 a physically constant spark air gap. It willbe noted that the portion of the electrical circuit between the two gapsis closed at all times and that the two gaps are electrically in series.It has been found that an electrode with a relatively large end surfaceinhibits sparking across the gap and a much lower voltage is required toionize or break down the air gap in the case of a needle pointelectrode. The end remote from the tapered portion of the electrode 82is suitably electrically connected to the lead wire 72.

In operation the flame control valve is adjusted so as to providesuflicient gas for the desired flame level and upon squeezing the lever62 towards the handle 12, the push rod 84 protruding into the fluidchamber 36 axially moves plunger 35 of the shutoff valve 34, therebyopening the valve 34 establishing gas to flow into and through thetubing 38 until the same reaches the outlet 54 of the nozzle 48.Simultaneously with causing the valve 34 to open, the radial movement ofthe lever 62 causes the piezoelectric element 58 to be squeezed againstframe 60 and to generate a voltage on electrode 66. The voltagegradually builds up to the desired level within the circuit constitutingthe electric assembly located Within the handle until the voltage isable to break down the gap existing between electrodes 68 and 78 andionize the space therebetween. Once the voltage reaches thispredetermined level it is quickly permitted to flow through the leadwire 72 and needle electrode 82 and is thereafter effective to ionizethe gap between the pointed end 83 of needle electrode 82 and theadjacent nozzle end (see 54) to ignite the gas at that location. Fullydepressing the lever 62 on or against the handle 12 is sufficient toprovide a plurality of sequential sparks at gap 54. The gas supply isshut off by releasing the lever 62 and permitting the rod 84 to moveaxially forward thereby releasing the plunger 35 from the open positionof the valve 34.

As the nozzle portion of the torch is mechanically connected to thehandle portion by means of a quick disconnect device of the bayonet typeand the electric circuitry located adjacent to gas carrying conduit 46and within nozzle 48 does not require a mechanical contact with thecircuitry located within the handle, it will be readily appreciated thatthe construction lends itself for a quick changeover between nozzles ofdifierent types. Moreover, the bayonet type coupler provides a fixedpredetermined orientation between the handle and the nozzle.

For most purposes it will be suflicient to manually hold the lever 62 inoperating position. However, a retaining latch, not shown, may beprovided to obviate the need for keeping the lever in a depressedcondition.

While there have been described what are at present considered to be thepreferred embodiments of this invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the invention, and it is aimed,therefore, in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. In a piezoelectrically ignited gas torch, having a handle;

valve means secured to said handle and connectible to a source of gasunder pressure;

a tube-like nozzle having an outlet for forming a spark gap and a gasconduit extending from said nozzle and secured to said handle, saidnozzle and conduit being formed at least partly of electricallyconductive material;

a tube between and connecting to said conduit and said valve forproviding a fluid passageway therebetween;

a piezoelectric igniter effective, upon actuation thereof,

to provide a high voltage spark source;

electric conductor means connected to said ignited and extending betweenthe latter and said nozzle; wherein the improvement comprises:

a solid, axially straight, cylindrical metal electrode substantiallyconcentrically disposed within said nozzle and supported therein byinsulator means located remote from the spark gap; and wherein saidelectrical conductor means includes a voltage breakdown control sparkgap.

2. In a piezoelectrically ignited gas torch according to claim 1,

wherein said electrode is of the needle type and the outer surfacethereof is predominantly uninsulated,

and wherein said electrode is tapered in the direction of the nozzleoutlet,

and the needle tip of said electrode terminates proximate to said outletto form a spark gap.

3. In a piezoelectrically ignited gas torch according to claim 1,

wherein said nozzle and said conduit are elongated and their axes ofelongation intersect and define an included angle of not less than 90degrees,

said nozzle having an axial, tubular, extension, remote from saidoutlet, axially spaced from the intersection of said axes;

said electrodes, more particularly the end remote from the nozzleoutlet, extending into said tubular extension;

and electrical insulation between said electrode and said extension.

4. In a piezoelectrically ignited gas torch according to claim 3,wherein said electrical conductor means is coupled to said electrodewithin said nozzle extension.

5. In a piezoelectrically ignited gas torch according to claim 4,wherein said electrical conductor means includes a portion insulatedfrom and extending externally alongside said conduit.

6. In a piezoelectrically ignited gas torch according to claim 1, and abayonet type quick disconnect and coupler means secured to said handleand connectible to said conduit;

and wherein said tube for providing said fluid passageway terminatesinto said coupler means.

7. In a piezoelectrically ignited gas torch according to claim 1,wherein said electrical conductor means is composed of two portions, thefirst portion thereof extending from said igniter to an outer surface ofsaid handle, and one end of the other portion is physically andelectrically juxtaposed, in spaced relation, to the end of said firstportion.

-8. In a piezoelectrically ignited gas torch according to claim 1,wherein said valve means includes a fluid inlet and outlet, and aplunger responsive shut ofi? valve positioned within the passageway ofsaid outlet.

9. In a piezoelectrically ignited gas torch according to claim 8, and aflame control valve interposed between the inlet and outlet of saidvalve means and effective for regulating the flow of fluid therebetween.

10. In a piezoelectrically ignited gas tor-ch according to claim 8,wherein said igniter includes a frame, piezoelectric means suitablydisposed within said frame, and means for manually actuating saidpiezoelectric means;

a pusher rod disposed in operative relation to said shutoff valve andconnected to said actuating means; the actuating means being effectiveto simultaneously apply a force upon said piezoelectric means togenerate a voltage and to move said pusher rod for operating saidshut-01f valve.

'11. In a piezoelectric device for igniting a combustible gas:

piezoelectric voltage generating means effective, upon actuationthereof, to provide a high voltage spark source;

a nozzle having a gas outlet, and a gas conduit extending from the otherend of said nozzle and connectible to a source of gas;

a solid, elongated, needle type, metal electrode substantiallyconcentrically disposed within said nozzle with the tapered end beinglocated in the direction .ofthe opening of the nozzle to form anignition gap therebetween;

electrical conductor means connected to and between said piezoelectricvoltage generating means, said noz zle, and said needle electrode toestablish an electric circuit and including a voltage breakdown controlgap effective to prevent ionization of the ignition gap until saidgenerating means has reached a predetermined voltage level.

12. In a piezoelectric ignition device:

manually actuated piezoelectric voltage generating means effective, uponactuation thereof, to provide a high voltage spark source;

an electric circuit electrically associated with said generating meansfor transmitting the generated voltage, said circuit including a sparkair gap and a voltage control gap, the two gaps being electrically inseries, said control gap being effective to block the voltage across itsgap until the voltage within the circuit has reached a predeterminedlevel, whereby the voltage then ionizes the voltage control gap andwithout any substantial dissipation of energy spanks across said sparkgap.

'13. In a piezoelectric ignition device according to claim 12, whereinelectrodes comprising part of said circuit are electricaly andphysically juxtaposed, the terminal end of each of said electrodesfacing each other having a spherical configuration spaced apart to formsaid voltage control gap.

14. In a piezoelectrically ignited gas torch, comprising: handle meansconnectible to a source of gas; manually actuated piezoelectric voltagegenerating means within said handle means, effective, upon actuationthereof to provide a high voltage spark source; a nozzle extending fromthe handle means and providing a spark gap and a conduit for the gas;and an electric circuit between said piezoelectric voltage generatingmeans and said spark gap and including a voltage level control gapelectrically in series with said spark gap, said control gap beingeffective to block the voltage across its gap until the voltage Withinsaid circuit has reached a predetermined level and ionizes the voltagecontrol gap and without any substantial dissipation of energy sparksacross said spark gap.

15. In a piezoelectric ignition device according to claim 14, whereinsaid voltage control gap is located between said nozzle and said handle.

16. In a piezoelectrically ignited gas torch according to claim 14,wherein each of the two gaps are constantly spaced.

17. In a piezoelectrically ignited gas torch according to claim 14,wherein the resistance across the voltage control gap is substantiallygreater than the effective resistance across the spark gap.

18. In a piezoelectrically ignited gas torch according to claim 14,wherein that portion of the electric circuit located between the twogaps is closed at all times.

19. In a piezoelectric ignition device according to claim 12, whereineach of the two gaps are constantly spaced.

20. In a piezoelectric ignition device according to claim 12, whereinthe resistance across the voltage control gap is substantially greaterthan the effective resistance across the spark gap.

21. In a piezoelectric ignition device according to claim 12, whereinthat portion of the electric circuit located between the two gaps isclosed at all times.

References Cited UNITED STATES PATENTS 2,402.,7 63 6/ 1946 Longini.2,672,924 3/ 1954 Anthes. 2,880,792 4/ 1959 Raskin. 3,070,153 12/ 1962Flynn. 3,255,803 6/1966 Hach et al.

FREDERICK L. MATTESO-N, JR., Primary Examiner.

E. G. FAVO-RS, Assistant Examiner.

U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, D.C. 20231 UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. 3,436,164April 1, 1969 Theodore F. Deucher It is certified that error appears inthe above identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 47, "a" has been omitted. Column 2, line 3, "to", firstoccurrence, should read the Column 3, line 48 "or" should read of line55 "exists" ShULl11 read exits Column 4 line 44 "the", first occurrencshould read that Column 5, line 40, "ignited" should read igniter Signedand sealed this 21st day of October 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, J r.

Commissioner of Patents Attesting Officer

